Peppermint is very difficult to grow from seed you'd do much better to take a cutting from an existing plant or buy a pot of to grow, it is generally cheap enough. Just make sure you keep it in a container as it is incredibly invasive.

As to the safflower this is an annual so you'll need to hold off sowing until next spring.

With Safflower, we grow it commercially here in the desert, so that tells you the amount of heat and sun it likes. Your best bet is probably a sunny south exposure with well drained soil. Peppermint is a sterile hybrid, Mentha spicata x M. aquatica, and actually doesn't normally produce seeds, so there is a chance that whoever sold you the seeds is scamming you. If the seeds are a mint, it is most likely Spearmint, which is highly variable as to taste when grown from seed.